Plow hitch assembly for vehicles

ABSTRACT

A hitch assembly provides removable connection of a plow assembly to a push beam assembly installed on a vehicle. The hitch assembly includes a draw latch assembly which engages the push beam assembly and pulls the plow assembly into position for pivotal attachment of the plow assembly to the vehicle. The draw latch assembly is activated by a power source, such as an hydraulic cylinder, and is further interconnected with a lift arm assembly such that further extension or activation of the hydraulic cylinder results in a raising or lowering of the plow blade. Also included is an easy connection and release mechanism for inserting and retracting pivot pins through corresponding brackets on the lift arm assembly and push beam assembly. A light tower assembly is removably attached to the push beam assembly such that when the plow is not in use, only the push beam assembly and its mounting brackets remain on the vehicle in a position below and rearward of a front bumper of the vehicle.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 09/243,908, filed Feb. 3,1999, by Philip J. Quenzi and Cal G. Niemela, entitled PLOW HITCHASSEMBLY FOR VEHICLES, now U.S. Pat. No. 6,178,699, the disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

This invention relates generally to plow assemblies for attachment to avehicle, and, more particularly, to a plow hitch assembly for easymounting and removal of a plow to and from the front of a vehicle.

A plow assembly for plowing snow or other loose or plastic materialssuch as sand, gravel, dirt of the like with a vehicle is typicallymounted to the front end of the vehicle to push the snow as the vehicleis driven forward. A mounting assembly is fixedly secured to a frame orchassis of the vehicle in order to provide a plurality of mountingattachments for a plow and hitch assembly to secure thereto. Thesemounting assemblies are generally positioned beneath a front bumper ofthe vehicle with attachment brackets extending forwardly and upwardly tofacilitate attachment. In order to move the vehicle when the plow is notin use, as well as to effectively push snow into a pile, a power sourcesuch as a hydraulic cylinder or the like is typically implemented toallow the plow blade of the plow assembly to be raised. This furtherrequires that the hitch assembly and/or a lift assembly be pivotallysecured to the mounting brackets extending from the vehicle.

When a typical plow assembly is to be attached to a vehicle having acorresponding mounting assembly secured thereto, the vehicle must bedriven to a point substantially close to the mounting edge of the liftassembly of the plow assembly. At that point a person must manuallyadjust the lift assembly both vertically and horizontally in order toalign the mounting holes or other attaching points on the lift assemblyto the corresponding mounting holes or attaching points on the mountingassembly secured to the vehicle. Once the mounting holes are properlyaligned, the same person, or a second person, must insert mounting pinsthrough the mounting holes in order to secure the plow assembly to thevehicle. This may be a rather difficult process, as these plowassemblies are of substantial weight and may even include a light tower,which provides headlamps substantially above the blade of the plow, anda power source on the lift assembly, thereby substantially adding to theoverall weight of the assembly which the person must then lift and moveto align with the vehicle.

Because the vehicles on which these plow assemblies are attached are notalways used to plow snow, such as every day transportation in theabsence of snow, the plow assemblies are typically manually detachablefrom the mounting assembly, which remains on the vehicle. However, evenwhen such assemblies are detached from the vehicle, the brackets andother connection points of many mounting assemblies protrude forward andabove the bumper of the vehicle. This results in an unsightly appearanceof the vehicle and may further lead to damage of the mountingattachments as they may become bumped or otherwise damaged over the timeperiod when the plow assembly is not attached to the vehicle.

While some plow assemblies have addressed this concern by implementing amounting assembly which remains substantially rearward of the bumper ofthe vehicle when the remainder of the plow assembly has been detachedtherefrom, it is then a difficult process to attach and detach the liftassembly of the plow onto the mounting assembly, since the mountingattachments are more difficult to reach due to their location beneathand rearward of the bumper. Therefore, this mounting process typicallyrequires persons attaching the plow to the vehicle to be in a ratherawkward and uncomfortable position as they attempt to reach the mountingholes beneath the bumper and insert the mounting pins therethrough whilesimultaneously supporting the lift assembly such that the holes arealigned. Similar difficulties are encountered when detaching the plowassembly from the mounting assembly on the vehicle.

Therefore, there is a need in the art for a snowplow assembly whichprovides for easy mounting and connecting of the plow assembly to thevehicle. The plow assembly must substantially detach from the vehiclesuch that a minimal number of components or brackets remain on thevehicle when the plow is not in use. The mounting attachments which aresecured to the vehicle should not be visible along the front or sides ofthe vehicle such that they will avoid damage or injury to people whenthey are not in use. Furthermore, the plow assembly must be pivotallyattached to the front of the vehicle without requiring a great deal oflifting and adjusting of the assembly by a person mounting the plow to avehicle.

SUMMARY OF THE INVENTION

The present invention is intended to provide a plow assembly which iseasily mounted to or detached from a vehicle, and especially the frontof a vehicle, with a minimal requirement for manual exertion.

According to a first aspect of the invention, a plow hitch assembly isadapted for mounting a plow on a vehicle which has a frame and a bumper.A push beam assembly is secured to the frame of the vehicle and thehitch assembly comprises a lift arm assembly, a draw latch assembly anda power source. The lift arm assembly has a first and second end, wherethe first end is adapted for connection with a plow blade and the secondend is adapted to removably and pivotally connect to the push beamassembly. The draw latch assembly selectively pulls the lift armassembly toward the push beam assembly and pivots the lift arm assemblyrelative to the push beam assembly to vertically move the plow blade.The power source is interconnected with the lift arm assembly and thedraw latch assembly and is operable to at least partially move a portionof the draw latch assembly such that the draw latch assembly engages thepush beam assembly and pulls the lift arm assembly toward the push beamassembly. The power source is further operable to at least partiallypivot the lift arm assembly relative to the push beam assembly and atleast a portion of the draw latch assembly so as to vertically move theplow blade.

According to another aspect of the present invention, a hitch assemblyis adapted for mounting a plow on a vehicle which has a frame and abumper. The hitch assembly comprises a push beam assembly, a lift armassembly, at least two coaxial mounting pins and a mounting lever. Thepush beam assembly is adapted to attach to the frame of the vehicle andincludes at least two first mounting flanges extending outwardlytherefrom at spaced positions. Each of these mounting flanges has afirst mounting opening therethrough. The lift arm assembly has a firstend and a second end, where the first end is adapted for connection witha plow blade and the second end is adapted to removably and pivotallyconnect to the push beam assembly. The second end of the lift armassembly includes at least two second mounting flanges, each of whichhas a second mounting opening therethrough. The at least two mountingpins pivotally attach the lift arm assembly to the push beam assemblysuch that the lift arm assembly pivots relative to the push beamassembly about a first pivot axis defined by the mounting pins. Each ofthe mounting pins is at least initially positioned adjacent to one ofthe first and second mounting openings and removably insertable througha corresponding pair of the first and second mounting openings of thepush beam assembly and the lift arm assembly when the first mountingopenings are aligned with the second mounting openings. Preferably, amounting lever is also included which is pivotable about a lever axis ina first direction and a second, opposite direction. The mounting leveris interconnected with the at least two mounting pins such that themounting pins engage the second mounting openings of the lift armassembly and the first mounting openings of the push beam assembly topivotally secure the lift arm assembly to the push beam assembly inresponse to a rotational movement of the mounting lever in the firstdirection. The mounting pins are withdrawn from at least one of thefirst and second mounting openings to detach the lift arm assembly fromthe push beam assembly in response to a rotational movement of themounting lever in the second direction.

According to yet another aspect of the present invention, a plowconnection assembly is adapted for mounting a plow on a vehicle whichhas a frame and a bumper. The plow connection assembly comprises a pushbeam assembly, a lift arm assembly and a draw latch assembly. The pushbeam assembly is secured to the frame of the vehicle and is positionedsubstantially rearward of the bumper of the vehicle. The lift armassembly has a first and second end. The first end of the lift armassembly is adapted for connection with a plow blade and the second endis adapted to removably and movably connect to the push beam assembly.The draw latch assembly is pivotally interconnected with the lift armassembly and extends from the second end of the lift arm assembly. Thedraw latch assembly is operable to pivot relative to the lift armassembly to engage the push beam assembly and pull the lift arm assemblytoward the push beam assembly for connection thereto.

These and other objects, advantages, purposes and features of thisinvention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a plow and hitch assembly attached tothe front of a vehicle in accordance with the present invention;

FIG. 2 is an upper rear perspective view of the push beam assembly ofthe present invention adapted for attachment to the frame or chassis ofa vehicle;

FIG. 3 is an upper front perspective view of the push beam assembly ofFIG. 2;

FIG. 4 is an upper rear perspective view of a lift arm assembly of thepresent invention;

FIG. 4a is an upper rear perspective view of the kickstand assembly anda lift stop arm of the lift arm assembly of FIG. 4;

FIG. 5 is an underside rear perspective view of the lift arm assembly ofFIG. 4;

FIG. 6 is an upper rear perspective view of the draw latch assembly ofthe present invention;

FIG. 6a is an upper rear perspective view of an intermediate link of thedraw latch assembly of FIG. 6;

FIG. 7 is a top plan view of the draw latch assembly of FIG. 6;

FIG. 8 is a bottom plan view of the draw latch assembly of FIG. 6;

FIG. 9 is an upper rear perspective view of a light tower assembly ofthe present invention;

FIG. 10 is an underside rear perspective view of a plow and hitchassembly of the present invention;

FIG. 11 is a top plan view of the plow and hitch assembly of FIG. 10;

FIG. 12 is an underside plan view of the plow and hitch assembly of FIG.10;

FIG. 13 is a side view of the plow and hitch assembly as it is detachedfrom the vehicle and a support stand is in a lowered position to supportthe assembly;

FIG. 14 is a side view of the plow and hitch assembly of FIG. 13 as amounting link of the draw latch assembly is raised toward a push beamassembly attached to the vehicle;

FIG. 15 is a side view of the plow and hitch assembly of FIG. 13 as adraw link of the draw latch assembly is pivoted to engage the push beam;

FIG. 16 is a side view of the plow and hitch assembly of FIG. 13 afterthe lift arm assembly has been pivotally secured to the push beamassembly and the support stand has been moved to a raised position;

FIG. 17 is a side view of the plow and hitch assembly of FIG. 13 withthe plow and lift arm assembly shown in a raised position;

FIG. 18 is an upper rear perspective view of a lift arm assemblyaccording to an alternate embodiment of the present invention;

FIG. 19 is an underside front perspective view of the lift arm assemblyof FIG. 18;

FIG. 20 is a side view of a plow and hitch assembly incorporating thelift arm assembly of FIG. 18, with the mounting link of the draw latchassembly raised toward the push beam on a vehicle and a mounting leverpivoted upward to disengage a pair of mounting pins from theirrespective mounting brackets;

FIG. 21 is a side view of the assembly in FIG. 20 with the mountinglever pivoted to engage the mounting pins into their respective mountingbrackets;

FIG. 22 is an upper rear perspective view of the lift arm and draw latchassemblies of the plow and hitch assembly of FIG. 20;

FIG. 23 is a side view of a plow and hitch assembly similar to the oneshown in FIG. 20, incorporating a draw link and support member inaccordance with an alternate embodiment of the present invention;

FIG. 24 is an upper rear perspective view of the lift arm and draw latchassemblies of the plow and hitch assembly shown in FIG. 23; and

FIG. 25 is a schematic illustration of a plurality of hydrauliccylinders and solenoid valves preferably incorporated in the plow andhitch assembly according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now specifically to the drawings, and the illustrativeembodiments depicted therein, there is shown in FIG. 1 a hitch assembly10 attached to a vehicle 12, which may be a pickup truck, sport utilityvehicle, 4×4 vehicle, or any other vehicle capable of pushing snow orthe like with a plow. The plow assembly 10 may be attached to a front 12a or rear (not shown) of vehicle and comprises a mounting assembly orpush beam assembly 14, a lift arm assembly 16, a draw latch assembly 18and a light tower assembly 20. The push beam assembly 14 is adaptable tofixedly mount to a frame or chassis (not shown) of vehicle 12 and ispreferably positioned such that it is positioned entirely beneath andrearward of a front bumper 22 of vehicle 12. Lift arm assembly 16 mayinclude a plow blade 24 pivotally mounted at a forward end 26, and ispivotally attached to push beam assembly 14 about a generally horizontalaxis such that plow blade 24 may be raised or lowered vertically by apower source or hydraulic cylinder 28. Draw latch assembly 18 ispivotally secured to lift arm assembly 16 and is operable to engage pushbeam assembly 14 when lift arm assembly 16 is not pivotally attached topush beam assembly 14, and pull lift arm assembly 16 into position formounting. Hydraulic cylinder 28 is interconnected between front end 26of lift arm assembly 16 and draw latch assembly 18, so as to beselectively operable to pull lift arm assembly 16 into alignment withpush beam assembly 14 and is further operable to raise or lower lift armassembly 16 and plow blade 24, as discussed in detail below. Light towerassembly 20 includes a pair of headlamps 30 which provide light over topof plow blade 24 as plow blade 24 generally interferes with standardheadlamps 32 of vehicle 12, especially when raised.

Lift arm assembly 16 and draw latch assembly 18 are easily attached as aunit to push beam assembly 14, since draw latch assembly 18 is operableto pull lift arm assembly 16 into alignment with push beam assembly 14,thereby avoiding excessive manual moving or lifting of lift arm assembly16. Preferably, push beam assembly 14 is substantially below andrearward of bumper 22 of vehicle 12, such that when draw latch assembly18 and lift arm assembly 16 are detached from push beam assembly 14,there are no brackets or other connection points visible on vehicle 12.Light tower assembly 20 is also removably mounted to push beam assembly14 and may easily be removed therefrom when not in use.

Push Beam Assembly

Referring now to FIGS. 2 and 3, push beam assembly 14 comprises asubstantially horizontal beam 36 extending laterally between twosubstantially vertical vehicle mounting plates 38 and welded, bolted orotherwise secured therebetween. Vehicle mounting plates 38 are bolted orotherwise secured to the frame or chassis of vehicle 12 and will not bedescribed in great detail, as they are adaptable for attaching push beamassembly 14 to an appropriate vehicle, and thus may vary according tothe vehicle on which they are to be mounted. Extending forwardly alongpush beam 36 are at least two mounting extensions or brackets 40laterally spaced apart along push beam 36. Mounting brackets 40 extendsubstantially forwardly of push beam 36 and include a closed mountinghole or slotted opening 40 a at a forward end 40 b of mounting brackets40. The mounting hole 40 a is preferably slotted to facilitate alignmentof mounting hole 40 a with a corresponding mounting hole on lift armassembly as discussed below. A guide bracket 42 is positioned laterallyto one side of each mounting bracket 40 and also extends forwardly ofpush beam 36. Guide brackets 42 include a slotted opening 42 b towardtheir forward end 40 b. Slotted opening 42 b widens toward forward end40 b to form a substantially V-shaped opening in guide bracket 42. Apair of laterally spaced light support brackets 44 are also attached topush beam 36 and extend forwardly and upwardly therefrom. Each lightsupport bracket 44 includes a laterally extending pin 44 a positionednear push beam 36 and a substantially cylindrical hole or passageway 44b through a distal end 44 c of light bracket 44 which is spaced frompush beam 36. Mounting bracket 40, guide bracket 42 and light bracket 44may be welded, bolted or otherwise secured to push beam 36 and extendgenerally forwardly therefrom yet preferably do not extend beyond bumper22 of vehicle 12 when push beam assembly 14 is installed to vehicle 12.Preferably, light brackets 44 are positioned laterally outwardly frommounting bracket 40 and guide bracket 42. Mounting bracket 40 ispositioned substantially near guide bracket 42 and is also preferablypositioned laterally outward from guide bracket 42, as shown in FIGS. 2and 3.

Lift Arm Assembly

Referring now to FIGS. 4 and 5, lift arm assembly 16 is generallytriangular or A-shaped with a center lengthwise beam 50 connected to alaterally extending cross beam 52 at a rearward end 50 a of center beam50. A pair of support arms 54 extend from each end 52 a of cross beam 52to a forward end 50 b of center beam 50 to provide stability and supportto lift arm assembly 16. Forward end 50 b of center beam 50 furtherincludes a substantially cylindrical passageway 50 c (FIG. 5) extendingsubstantially vertically therethrough. Passageway 50 c is for pivotallyconnecting plow blade 24 (FIG. 1) to lift arm assembly 16. Plow blade 24may be secured by a pin (not shown) extending through a bracket orcollar on a rearward portion of plow blade 24 through passageway 50 c,such that the pin provides a vertical pivot axis about which plow blade24 pivots from side to side. This sideways pivoting is preferablyaccomplished by a pair of hydraulic cylinders 244 (FIGS. 1 and 20), eachone being preferably pivotally secured between a set of mountingbrackets 70 extending laterally outward from each end 52 a of cross beam52 and a pair of attachment brackets (not shown) on a rearward side ofplow blade 24. A hydraulic pump 56 or other power source for activatinghydraulic lift cylinders 244 and 28, and any other hydraulic cylinderswhich may be included in hitch assembly 10, is secured on an uppersurface of center beam 50.

Extending rearwardly from a center portion 52 b of cross beam 52 of liftarm assembly 16 are a pair of corresponding draw latch mounting brackets58, spaced laterally apart and each with a mounting hole or opening 58 atherethrough. A pin 130 may be provided in lift arm assembly 16 forpivotally mounting draw latch assembly 18 to brackets 58, as discussedbelow. Cross beam 52 further includes a set of push beam mountingbrackets or flanges 60 positioned substantially near each lateral end 52a of cross beam 52. Each push beam mounting bracket 60 preferablycomprises three rearwardly extending flanges or brackets, an outermounting flange 62, an outer bushing support flange 64 and an innerbushing support flange 66. Each flange or bracket is generally parallelto and spaced apart from the other brackets. Outer mounting flange 62preferably extends rearwardly of cross beam 52 and includes a mountinghole or opening 62 a therethrough for receiving a mounting pin 68. At arearward end 62 b of each outer mounting flange 62, there is preferablyan outwardly bent or flared section 62 c, which extends rearwardly andlaterally outwardly from rearward end 62 b of outer mounting flange 62.Each outer mounting flange 62 is preferably positioned at ends 52 a ofcross beam 52. Positioned laterally inwardly from each outer mountingflange 62 is outer bushing support 64, which also extends rearwardlyfrom cross beam 52 and includes a support hole or opening 64 a throughits rearward end 64 b. Positioned inwardly from each outer bushingsupport 64 is a corresponding inner bushing support 66, which alsoextends rearwardly from cross beam 52 and includes a support hole oropening 66 a through its rearward end 66 b. Inner bushing support 66further includes an inwardly bent or flared section 66 c extendingrearwardly and laterally inward from rearward end 66 b. A guide bushing72 is interconnected between support holes 64 a and 66 a through eachouter bushing support 64 and inner bushing support 66, respectively.Guide bushings 72 are substantially cylindrical in shape and have acylindrical hollow passageway (not shown) therethrough for receivingmounting pins 68 since holes 62 a are substantially coaxially alignedwith the passageway through guide bushings 72. Mounting pins 68 arepreferably substantially L-shaped with a cylindrical portion 68 a whichis extendable through holes 62 a, 64 a and 66 a in mounting brackets 62and bushing supports 64 and 66, respectively. Mounting pins 68 mayinclude a hole or opening 68 b through one end for receiving a lock pin74, or may have other means for preventing mounting pins 68 from beingaccidentally removed from the mounting brackets.

As best shown in FIG. 5, center beam 50 includes a rearward projectingflange 50 d along each side of center beam 50. Flanges 50 d arepositioned substantially adjacent to an underside surface 52 c of crossbeam 52, and spaced apart from a pair of corresponding downwardlydepending brackets 76 extending from lower surface 52 c of cross beam52. Each bracket 76 and each extension 50 d are positioned laterallyapart with a corresponding pin 78 extending therethrough, to form apivot axis 78 a for a lift stop link 80. Each lift stop link 80 is asubstantially rectangular shaped bar and is pivotally secured at one end80 a to lift arm assembly 16 by pin 78 and brackets 76 and 50 d andextends forwardly therefrom such that a forward end 80 b is within achannel 82 a extending along each side of center beam 50. Channels 82 aalong center beam 50 are preferably formed by a pair of L-shapedbrackets 82 extending lengthwise along each side of center beam 50 andcurving inwardly at a lower edge 50 e of center beam 50 to form asubstantially horizontal track 82 b. L-shaped brackets 82 are spacedoutwardly from center beam 50 by at least two spacers 94, so as toprovide a space in which lift stop link 80 is positioned between thebrackets 82 and the sides of center beam 50.

Lift stop links 80 include a pair of connecting members 84 and 85, whichare welded or otherwise secured to links 80 and extend substantiallyvertically from a corresponding lift stop link 80 on either side ofcenter beam 50. Connecting members 84 and 85 are connected at an upperend by a connecting pin or rod 84 a (FIG. 4), such that movement of onelift stop link 80 will cause substantially the same movement of theother lift stop link 80 on the opposite side of center beam 50. Agenerally horizontally extending slot 84 b is formed along a lower end84 c of one of the vertical connecting members 84.

A kickstand or support assembly 88 (FIGS. 4, 4 a and 5) is preferablypositioned on one side of lift arm assembly 16 to support lift armassembly 16 when lift arm assembly 16 is not pivotally connected to pushbeam assembly 14. Support assembly 88 includes a substantially L-shapedleg 88 a with a foot 88 b at one end and includes a shaft 86. Shaft 86extends from leg 88 a through an outer kickstand bracket 90 and an innerkickstand bracket 91 and is pivotally secured therethrough. Acylindrical extension 86 a extends from an end 86 b of shaft 86 and ispositioned eccentrically from a longitudinal axis 86 c of shaft 86.Cylindrical extension 86 a, is preferably welded within a groove 86 dformed along an outer portion of shaft 86 and extends inward of innerkickstand bracket 91 to engage slot 84 b in connecting member 84, asbest shown in FIG. 4a. Because cylindrical extension 86 a is positionedoff-axis along shaft 86, rotational movement of the kickstand leg 88 aand foot 88 b causes cylindrical extension 86 a to move along an arcuatepath about axis 86 c. This results in a vertical movement of cylindricalextension 86 a which further causes a corresponding vertical movement ofconnecting member 84 and thus a corresponding vertical movement of bothlift stop links 80. Therefore, a rotational movement of kickstandsupport assembly 88 causes both lift stop links 80 to move verticallyand thus pivot about pivot axis 78 a. More specifically, cylindricalextension 86 a is positioned along a lower portion of shaft 86 whensupport stand 88 is in a down or supporting position, such that whensupport stand 88 is pivoted into a raised position, as shown in FIG. 5,cylindrical extension 86 a is rotated upwardly about the axis 86 c ofshaft 86. This results in lift restraint links 80 being raised ascylindrical extension 86 a moves upwardly against vertical connectingmember 84. A spring 89 and pin 89 a may be included on outer kickstandbracket 90 and engage a notch 89 b on leg 88 a to provide resistance topivotal movement of support assembly 88 to its support position, therebysecuring support stand assembly 88 in its raised position.

Draw Latch Assembly

Referring now to FIGS. 6 through 8, draw latch assembly 18 comprises apair of mounting links 100, a pair of draw links 102, a pair of liftstop arms 104, a pair of intermediate links 106 and a pair of connectinglinks 108. Draw links 102 are spaced laterally apart from one anotherand have a generally curved or hook-shaped portion 102 b. Asubstantially horizontally extending connecting link pin 102 a extendsbetween the two draw links 102 and preferably extends laterallyoutwardly thereof. Connecting link pin 102 a is positioned at a lowerend of draw links 102 substantially opposite the hooked portions 102 band functions to provide a pivotal connection of connecting links 108,at a rearward end 108 a, between draw links 102 and to further provide aconnection for a pair of draw latch springs 110, as discussed below.Draw links 102 are pivotally secured between the rearward ends 100 a ofmounting links 100 about a bolt or pin 102 c. Pin 102 c is positionedthrough draw links 102 relative to connecting link pin 102 a preferablysuch that rearward movement of connecting links 108 causes a rotation ofdraw links 102 about pin 102 c such that the curved portions 102 b ofdraw links 102 move generally forward relative to mounting link 100.

As shown in FIG. 6a, intermediate links 106 are generally triangularshaped and include three pivot holes or openings therethrough. An upperhole 106 a is positioned in an upper portion of each intermediate links106 and provides for a pivotal connection of intermediate links 106 toboth mounting link arm 100 and lift arm assembly 16 by pin 130. A lowerforwardly positioned hole 106 b through each intermediate link 106provides for a pivotal connection of hydraulic cylinder 28, while alower rearward hole 106 c provides for a pivotal connection toconnecting links 108 at a forward end 108 b of connecting links 108.Hydraulic cylinder 28 preferably includes at least one compressionspring or a series of compression springs 28 c positioned along a rodportion 28 d (FIG. 7) of hydraulic cylinder 28 for biasing rod portion28 d in a partially extended position when hydraulic cylinder 28 is notpressurized. This biases mounting links 100 in an upward position, asdiscussed below. Connecting links 108 are substantially straight barlinkages which are thus pivotally interconnected at lower rearward holes106 c of intermediate links 106 and at lower pin 102 a of draw links 102and positioned between the two mounting links 100.

Mounting links 100 include an upwardly extending flange for pivotalconnection to lift arm assembly 16, and include a substantiallycylindrical hole or opening 100 a therethrough. Mounting links 100extend generally rearwardly from openings 100 a and include asubstantially flattened section 100 b along an upper edge toward theirrearward end 100 c. Flat region 100 b provides for a contact point withan underside of push beam 36 when draw latch assembly 18 engages pushbeam 36, as discussed in detail below. Pivot pin 102 c of draw links 102pivotally connects draw links 102 to mounting links 100 at a locationbelow and substantially rearward of flat sections 100 b on mountinglinks 100. A recess or indentation 100 e is preferably formed along alower rearward edge of each mounting link 100 for receiving pins 102 aon draw links 102 and preventing over-rotation of draw links 102relative to mounting links 100. A spring retaining pin 100 d extendsgenerally through a center portion of mounting links 100 and furtherprotrudes laterally outwardly therefrom. Spring retaining pin 100 dfunctions to provide a connection point for draw latch spring 110 andfurther provides a pivotal connection for a pair of lift stop arms 104at a rearward end 104 a of lift stop arms 104. The stop arms 104 aregenerally straight bar linkages extending in a generally forwarddirection from second spring retaining pin 100 d along outer sidesurface of each mounting link 100. Stop arms 104 are also connected toeach other at their forward end 104 b by a substantially cylindrical andhorizontally extending slide pin at 104 c. Slide pin 104 c extendssubstantially horizontally between front ends 104 b of lift stop arms104 and further protrudes laterally outwardly therefrom. Slide pin 104 cmay also include a spacer positioned between the lift stop arms 104 toprovide lateral support of lift stop arms 104. Preferably, a spacer isalso included along pins 102 a, 102 c and 100 d, to provide lateralsupport between the pair of mounting links 100 and pair of draw links102.

As shown in FIGS. 4, 5, 10-17 and 22, intermediate links 106 arepositioned between mounting links 100 and are pivotally connected toboth the mounting links 100 and lift arm assembly 16 by insertion of pin130 through holes 106 a and 100 a of intermediate links 106 and mountinglinks 100, respectively, and through holes 58 a in bracket 58. Ashydraulic cylinder 28 provides rearward motion of the lower portion ofthe intermediate links 106, through the pivotal interconnection withhole 106 b, intermediate links 106 therefore pivot rearwardly about apivot axis defined by opening 106 a. This rearward motion of the lowerportion of intermediate links 106 results in a rearward movement ofconnecting links 108, and a corresponding movement of the lower portionsof draw links 102, thereby pivoting draw links 102 about pivot axis 102c at the rearward end of mounting links 100. Although shown anddescribed as several linkages being pivoted by a hydraulic cylinder,clearly other means of moving linkages in order to pivot a draw linkand/or a mounting link may be implemented without affecting the scope ofthe present invention.

Referring now to FIG. 9, light tower assembly 20 generally comprises apair of headlamps 30, a pair of substantially vertical and parallel sidebars 118 and upper and lower cross members 120 and 122, respectively.Headlamps 30 are mounted to a pair of brackets 120 a positioned at eachend of upper cross member 120. Lower cross member 122 provides lateralsupport of vertical side bars 118 and is welded or otherwise securedbetween the two side bars 118 at a location substantially beneath uppercross member 120. Sidebars 118 are substantially vertical members andinclude a curved section 118 a at their lower end. Curved section 118 afurther includes a slot 118 b at its lower end and a hole or opening 118c that is positioned substantially above and forwardly of slot 118 b. Apair of spring extendable mounting pins 124 may also be included, eachof which preferably consists of an outer threaded portion 124 a and aninner pin 124 b, which is spring biased to an extended position. Innerpin 124 b includes a tee handle 124 c on a laterally outboard end whichmay be pulled outwardly to retract inner pin 124 b into a retractedposition within outer threaded portion 124 a. Inner pins 124 b may berotatable when in this retracted position in order to temporarily securethem in the retracted position to facilitate attachment of light towerassembly 20 to push beam assembly 14. Mounting pins 124 are preferablythreadably engaged or otherwise secured in holes 118 c such that innerpins 124 b are extendable therefrom and further engageable with thelight tower mounting bracket 44 when light tower assembly 20 is alignedwith the push beam assembly 14, as discussed in detail below.

Referring now to FIGS. 10-12, hitch assembly 10 is shown in its fullyassembled state, yet separate from a vehicle. Draw latch assembly 18 ispivotally connected to draw latch bracket 58 of lift arm assembly 16 bypin or bolt 130. Pin 130 extends through draw latch bracket 58, mountinglinks 100 and intermediate links 106, such that both intermediate links106 and mounting links 100 are pivotable relative to lift arm assembly16 and further pivotable relative to one another about a pivot axis 130a. Hydraulic cylinder 28 of draw latch assembly 18 is also pivotallysecured to lift arm assembly 16 at a forward end 50 b of center beam 50of lift arm assembly 16. Therefore, activation of hydraulic cylinder 28will cause rotational movement of intermediate links 106 or mountinglinks 100 or both relative to lift arm assembly 16. Slide pins 104 c oflift stop arms 104 slide within the channel 82 a formed by channelplates 82 and spacers 94 connected to the sides of center beam 50 oflift arm assembly 16. As discussed above, lift stop links 80 are alsopositioned such that forward end 80 b of stop links 80 is within thechannels 82 a and positioned laterally outwardly from the sidewall ofcenter beam 50. Lift stop links 80 pivot about pivot pins 78 such thatin a lowered position, corresponding to a lowered or support position ofthe kickstand or support assembly 88, rearward movement of slide pins104 c along channel 82 a is limited as the outward portions of slidepins 104 c engage the end 80 b of lift restraint links 80 when slidepins 104 c are moved rearwardly along channel 82 a. As discussed furtherbelow, when rearward movement of slide pins 104 c is limited, lift stoparms 104 prevent further pivoting of mounting links 100, which resultsin pivoting of only intermediate links 106 and therefore draw links 102upon any further rearward movement on the part of hydraulic cylinder 28.

As best shown in FIGS. 11 and 12, lift arm assembly 16 is pivotallysecured to push beam assembly 14 by pivot pins 68 engaging the push beammounting brackets 60 of lift arm assembly 16 when they are aligned withthe lift arm assembly mounting brackets 40 of push beam assembly 14.More specifically, when slots 42 b of guide brackets 42 on push beamassembly 14 engage guide bushings 72 positioned between inner and outerbushing supports 66 and 64, pivot holes 40 a of lift arm assemblymounting brackets 40 are vertically adjusted so as to align withcorresponding pivot holes 62 a on outer mounting flanges 62 of lift armassembly 16 and with the passageways through guide bushings 72. Pivotpins 68 are then inserted through the holes 62 a and 40 a, and furtherinserted through guide bushings 72 and the corresponding bushingsupports 64 and 66, such that each pin 68 protrudes through an innerside 66 d of each inner bushing support 66. Lock pins 74, or other meansof preventing pivot pins 68 from being removed from the mountingbrackets, are then inserted through or otherwise secured to the inwardlyprotruding portions of pivot pins 68. Lift arm assembly 16 is thereforepivotally secured about the pivot pins 68 connecting lift arm assembly16 to push beam assembly 14. The pivot pins 68 are substantiallycoaxially aligned, such that a single pivot axis 68 a is formed by thisconnection. However, due to the additional pivot axis 130 a defined bypin 130 connecting mounting links 100 and intermediate links 106 tobrackets 58 of lift arm assembly 16, a second pivot axis 130 a isprovided that is not coaxially aligned with the pivot axis formed bypivot pins 68. As best seen in FIG. 11, pivot axis 130 a is spacedsubstantially forwardly of the pivot axis 68 a formed by the pivot pin68 and, as best seen in FIG. 17, pivots upwardly about pivot axis 68 awhile lift arms assembly 16 pivots relative to both push beam assembly14 and draw latch assembly 18.

As best shown in FIGS. 11 and 13, light tower assembly 20 is removablysecured to push beam assembly 14. Slots 1 18 b of vertical sidebars 118engage pins 44 a protruding laterally outwardly from light towerbrackets 44 on push beam 36 as holes 118 c and mounting pins 124 invertical sidebars 118 are aligned with corresponding holes 44 b in lighttower mounting brackets 44. Inner pins 124 b are extended to theirextended position which inserts inner pins 124 b through holes 44 b,thereby preventing relative movement between light tower assembly 20 andpush beam assembly 14. Because lock pins 124 are preferably springloaded, inner pins 124 b remain biased within the holes 44 b, such thataccidental removal of lock pins 124 from light tower assembly 20 andpush beam assembly 14 is substantially precluded.

Attachment and Operation

The attachment and operation of the draw latch assembly 18 and lift armassembly 16 and push beam assembly 14 will now be discussed in detailwith respect to FIGS. 13 through 17. As shown in FIG. 13, draw latchassembly 18 is pivotally connected to lift arm assembly, as discussedabove, and support stand assembly 88 is in its lowered position orsupport position to support arm lift assembly 16 and draw latch assembly18 above the ground when they are not attached to push beam assembly 14.When support stand 88 is in its support position, cylindrical pin 86 aextending from shaft 86 of the kickstand assembly 88 is rotated to itslowered position within slot 84 b of vertical connecting member 84. Thispositions lift stop links 80 in their lowered position, since they arepivoted about pivot pin 78 such that a forward end 80 b of each liftstop link 80 is positioned within channel 82 a. Hydraulic cylinder 28 isretracted with pump and motor 56, such that compression springs 28 c onrod 28 d are compressed while intermediate links 106 are pivoted forwardand connecting links 108 are also moved forwardly, thus pivoting drawlinks 102 to their retracted or opened position about pivot pin 102 c onmounting links 100. Further retraction or rotation of draw links 102 isprevented as pin 102 a engages recesses 1 00 e along the lower edges ofmounting links 100. Therefore, further retraction of hydraulic cylinder28 results in a downwardly pivoting of mounting links 100 about pivotaxis 130 a, such that mounting links 100 and draw links 102 are in theirlowered positions as shown in FIG. 13. In order to connect the plow andhitch assembly to the push beam assembly 14, which is secured to vehicle12, vehicle 12 is then driven forward until push beam 36 is positionedforwardly of the curved ends 102 b of draw links 102.

Prior to draw latch assembly 18 and lift arm assembly 16 being connectedto push beam assembly 14, light tower assembly 20 may be easily securedto push beam assembly 14. This is accomplished by engaging slots 118 bon side bars 118 with the pins 44 a on light brackets 44. After the pins44 a are within slots 118 b, light tower assembly 20 may be easilypivoted about pins 44 a until holes 118 c and lock pins 124 in side bars118 are aligned with corresponding holes 44 b in brackets 44. Once theholes 118 c and 44 b are aligned, inner pins 124 b are preferablyrotated such that inner pins 124 b are extendable into their extendedposition, which results in inner pins 124 b inserting through holes 44 band securing light tower assembly 20 to push beam assembly 14. Lighttower assembly 20 may likewise be removed from push beam assembly 14 bypulling laterally outwardly on tee handle 124 c of pins 124 such thatinner pins 124 b are disengaged from holes 44 b. Inner pins 124 b mayalso be rotated to remain in their retracted position.

After vehicle 12 has been driven into position above draw latch assembly18, the electrical cables (not shown) may be connected betweenappropriate switches or controls within vehicle 12 and power source 56in a conventional manner. With vehicle 12 in the appropriate positionrelative to lift arm assembly 16, hydraulic cylinder 28 may be energizedto extend and push rearwardly on intermediate links 106 at pivotopenings 106 b. This causes a rearward rotation of intermediate links106 about pivot axis 130 a, as shown in FIG. 14. This rearward rotationof intermediate links 106 correspondingly moves connecting links 108 ina rearwardly direction relative to lift arm assembly 16. However,because draw latch springs 110 bias draw links 102 in their retractedand open position, the initial rearward movement of connecting links 108functions to pivot mounting links 100 about pivot axis 130 a (in acounterclockwise direction in FIG. 14), as intermediate links 106likewise pivot thereabout, rather than to pivot draw links 102 aboutaxis 102 c. This is accomplished by selecting a coil spring 11O with aspring force greater than the resistance to rotation of mounting links100 about pivot axis 130 a.

As mounting links 100 are pivoted upward by the initial extension ofhydraulic cylinder 28, lift stop arms 104 are correspondingly movedrearward relative to lift arm assembly 16. This results in slide pins104 c also moving or sliding rearward along channel 82 a of lift armassembly 16. At a point substantially corresponding to a position ofmounting links 100 being in a substantially horizontal position and/orwhere the flat section 100 b on mounting links 100 contacts underside 36a of push beam 36, slide pins 104 c of lift stop arms 104 contactforward end 80 b of lift stop links 80, as they are in their loweredposition corresponding to the support position of support stand 88. Thecontact of slide pins 104 c with lift stop links 80 substantiallyprecludes further rearward travel of lift stop arms 104, therebypreventing mounting links 100 from pivoting further upward beyond theirhorizontal position.

At this point, further rotational movement of mounting links 100 isprecluded by lift stop links 80 and lift stop arms 104. Furtherextension of lift cylinder 28 thus provides further rotational andrearward movement of intermediate links 106 about pivot axis 130 a,thereby further moving connecting links 108 in a rearwardly direction.Because mounting links 100 cannot pivot further about pivot axis 130 a,the further rearward movement of connecting links 108 rotates draw links102 about pivot axis 102 c on mounting links 100 (in a counterclockwisedirection in FIG. 14), as the spring force of springs 110 is thenovercome by the hydraulic cylinder 28.

As shown in FIG. 15, with the lift support assembly 88 in its supportposition, and slide pins 104 c thus contacting lift stop links 80,further actuation or extension of hydraulic cylinder 28 pushesintermediate links 106 to pivot further about pivot axis 130 a, resultsin a pivoting of draw links 102 about their pivot axis 102 c. Draw links102 pivot such that the curved ends 102 bcontact a rearward portion 36 bof push beam 36. Further extension of hydraulic lift cylinder 28 causesfurther rotation of draw links 102, such that draw links 102 bear on therearward side 36 b of push beam 36 and draw or pull the hitch assembly10 with plow 24 attached toward vehicle 12. Draw links 102 continue topivot about pivot axis 102 c on mounting links 100 until the mountingholes 40 a and 62 a are properly aligned for easy insertion of pivotpins 68. Pivot pins 68 may then be easily inserted through the mountingholes and secured therein by lock pins 74 or the like.

As vehicle 12 is driven toward lift arm assembly 16 and draw latchassembly 18 and/or while draw latch assembly 18 is pulling lift armassembly 16 into position adjacent to push beam assembly 14, bothvertical and lateral positioning of lift arm assembly 16 is aided by themounting brackets on both lift arm assembly 16 and push beam assembly14. More specifically, the substantially V-shaped slots 42 b in guidebrackets 42 on push beam 36 initially engage guide bushings 72 on liftarm assembly 16 as the lift arm assembly 16 approaches push beamassembly 14. The mounting holes 40 a and 62 a on the mounting bracketsare vertically adjusted relative to one another as the guide bushings 72further engage V-shape slots 42 b, which narrow to a width substantiallyequal to the diameter of the guide bushings 72. When guide bushings 72are within the narrowed portion of slot 42 b, pivot holes 40 a and 62 aare substantially aligned relative to one another for insertion of pivotpins 68 therethrough. Furthermore, lateral adjustment of lift armassembly 16 relative to push beam assembly 14 is provided by theoutwardly flared sections 62 c of outer mounting flanges 62 and theinwardly flared sections 66 c of inner bushing supports 66. These flaredsections initially contact a forward edge of either the mounting bracket40 or the guide bracket 42 extending forwardly from push beam 36 andlaterally adjust the assembly such that both the guide bracket 42 andmounting bracket 40 slide between the inner and outer bushing supports64 and 66 and between the outer bushing support 64 and outer mountingflange 62, respectively.

After pivot pins 68 have been inserted through their respective mountingholes 40 a and 62 a to thereby establish pivot axis 68 a, support standassembly 88 may be pivoted into its raised position, as shown in FIG.16. By raising kickstand assembly 88, cylindrical extension 86 a inshaft 86 pivots upwardly within slot 84 b along vertical connectingmember 84 of lift stop link 80. This results in a upward movement oflift stop links 80, as they pivot about pivot pins 78 relative to liftarm 16. When support stand assembly 88 is in its fully raised position,as shown in FIG. 16, forward ends 80 b of lift stop links 80 are thusraised to a level above slide pins 104 c of lift stop arms 104, therebyagain allowing rearward movement of slide pins 104 c along channels 82 aof lift arm assembly 16. Because slide pins 104 c are connected tomounting links 100 by lift stop arms 104, this unrestrained movement ofslide pins 104 c allows for further rotational movement of mountinglinks 100 about pivot axis 130 a, which thus allows further rotation oflift arm assembly 16 relative to draw latch assembly 18 about axis 130a. In this position, compression springs 28 c maintain hydrauliccylinder 28 in a partially extended position even if there is a decreasein pressure within hydraulic cylinder 28. This holds mounting links 100in contact with push beam 36 when the plow is operated in a “float”position, where the blade is lowered for plowing and the hydrauliccylinder 28 is not fully pressurized, in order to allow the plow bladeto move or “give” in response to contacting an object while plowing.

Referring now to FIG. 17, hitch assembly 10 is shown in a raisedposition. This position results from further extension of hydrauliccylinder 28 while support stand 88 is in its raised position, asdiscussed above. As was described with respect to FIGS. 13 and 14,extension of hydraulic cylinder 28 normally causes rotation of mountinglinks 100 relative to lift arm assembly 16 about pivot axis 130 a whenslide pins 104 c are free to travel along channels 82 a. However,because draw links 102 are now engaged with push beam 36 and pivot pins68 are installed through the mounting brackets of lift arm assembly 16and push beam assembly 14, further upward rotation of mounting links 100is substantially precluded. Therefore, any further extension of ahydraulic cylinder 28 results in a lifting of the front end of lift armassembly 16 and thus of the plow blade 24, as lift arm assembly 16 ispivoted about pivot axis 130 a (in a clockwise direction in FIG. 17)relative to draw latch assembly 18 and about pivot axis 68 a relative topush beam assembly 14. Lift arm assembly 16, therefore, pivots about twopivots axes 130 a and 68 a in response to any further extension orretraction of hydraulic cylinder 28. This rotation of pivot axis 130 arelative to pivot axis 68 a causes the forward end of mounting links 100to move vertically upward as hydraulic cylinder 28 is extended, thusincreasing clearance between the forward end of mounting links 100 andthe ground when the plow is in its raised “transport” position.

Hitch assembly 10 therefore provides an assembly which provides for easyconnection to a vehicle and for raising and lowering of the plowassembly, all with only a single hydraulic cylinder or power source.Furthermore, as best shown in FIG. 13, a forwardmost portion of all ofthe mounting brackets or flanges extending forwardly from push beam 36beneath vehicle 12 terminate at a point substantially below and rearwardof a front edge 22 a of bumper 22 on vehicle 12. This allows for thelift arm assembly 16 and draw latch assembly 18 to be removed as a unitfrom vehicle 12. In addition, light tower assembly 20 may be separatelyremoved from push beam assembly 14. Thus, after both removal steps,there are no components left behind on vehicle 12 which may be visibleor easily damaged when the plow and hitch assembly 10 is not in use,except for the push beam assembly 14 which, as described above, is belowand behind the front bumper.

Alternate Embodiment

In an alternate embodiment of the present invention, as shown in FIGS.18-22, a hitch assembly 200 includes a lift arm assembly 16′ whichimplements a cable release mechanism to insert and retract mounting pins68′ in their respective mounting holes. This embodiment includes thesame draw latch assembly 18, push beam assembly 14 and light towerassembly 20 of the preferred embodiment and the same mounting brackets60 along the lift arm assembly described above. Accordingly, thediscussion of this embodiment will focus on the changes to lift armassembly 16′ and how the cable release system functions.

Lift arm assembly 16′ includes a release lever 202 which functions toboth allow for insertion and retraction of a pair of mounting pins 68′through corresponding mounting brackets 60 and 40 similar to themounting brackets of lift arm assembly 16, and push beam assembly 14discussed above, and also to raise and lower a pair of lift stop links204 (FIG. 19), as discussed below. Handle 202 includes a pair oflaterally spaced apart side members 206 and a laterally extending orhandle bar 208 which connects the side members 206 at one end. A secondlaterally extending bar 210 is preferably provided between the sidemembers 206 and further includes a spring pin 212 protrudingtherethrough. Handle 202 is positioned on an upper surface of the centerbeam 50 of lift arm assembly 16′ and is located forwardly of cross beam52. A substantially L-shaped frame or bracket 214 is secured to centerbeam 50 in a position forwardly of handle 202 and extending rearwardlyand over a pivot axle 216, about which handle 202 is pivoted. Pivot axle216 includes a pair of substantially circular disks 218 extending inplanes generally perpendicular to pivot axle 216 and spaced laterallyapart along pivot axle 216, which has a diameter substantially less thanthe diameter of the circular disks 218. Circular disks 218 are alsopositioned eccentrically with respect to an axis 216 a of cylindricalaxle 216 (FIG. 18), and are positioned immediately adjacent to both theupper surface of center beam 50 and a vertical portion 214 a of L-shapedbracket 214 such that when handle 202 is rotated, circular disks rotateand slidably engage the upper surface of center beam 50. Rotationalmovement of handle 202 about its pivot axis 216 a also results in acorresponding substantially vertical movement of pivot axle 216 since itis pivoted eccentrically with the rotating circular disks 218. Circulardisks 218 remain in contact with L-shape bracket 214 and center beam 50and are substantially precluded from rearward movement due to theirconnection with lift stop links 204, as discussed below.

Lift stop links 204 are each interconnected to a side of handle 202 by aconnecting member 220, which extends rearwardly and downwardly frompivot axle 216 of handle 202, and is welded or otherwise secured to eachlift stop link 204. Rotation of handle 202 raises pivot axle 216 andconnecting members 220, which then raise lift stop links 204. Therefore,rotation of handle 202 accomplishes the same vertical movement of liftstop links 204 as rotation of support stand assembly 88 provides forlift stop links 80 in hitch assembly 10. Connecting member 220 furtherfunctions to maintain the position of handle 202 substantially adjacentto L-shaped bracket 214, as connecting member substantially precludesrearward movement of handle 202.

The release mechanism of lift arm assembly 16′ preferably includes apair of cables 222, which interconnect handle 202 to mounting pins 68′.Cables 222 are connected at one end 222 a to cylindrical axle 216 andare wound around cylindrical axle 216 on each end thereof and spacedlaterally outward from circular disks 218. As best shown in FIG. 19,cables 222 then preferably extend downwardly and rearwardly fromcylindrical axle 216 and are guided rearwardly as they curve about alower forward edge 53 of cross beam 52. Cables 222 then extendrearwardly beneath cross beam 52 and are further guided at upwardly andfurther rearwardly by a lower rearward edge 53 a, which allows cables222 to curve upwardly toward a cable guide 226. Cable guide 226 ismounted at a rearward portion of draw latch assembly mounting bracket 58and includes a pair of circular disks 226 a between which cables 222 areguided and a cylindrical portion 226 b around which cables 222 arecurved so that they are directed outwardly toward mounting brackets 60on lift arm assembly 16′. Each cable 222 is then fed through a slottedopening 228, which is formed in a substantially L-shaped bracket 230which is welded or otherwise secured to a rearward portion of crossbeam52 and extending rearwardly therefrom. A cylindrical extension 230 aextends laterally outward from each bracket adjacent the slotted opening228. Cables 222 are fixedly secured to an end 68′a of pivot pins 68′such that pivot pins 68′ may be pulled from mounting holes 62 a and 40 aof mounting bracket 62 on lift arm assembly 16′ and mounting bracket 40on push beam assembly 14, respectively. A compression spring 232 ispositioned between each L-shaped bracket 230 and its corresponding pivotpin 68′. Compression springs 232 receive cylindrical extension 230 a atone end and ends 68′ of pivot pins 68′ at another end. Compressionsprings 232 exert a force to bias pivot pins 68′ in their extendedposition through mounting holes 40 a and 62 a, as shown in FIG. 18.

Therefore, when handle 202 is rotated upward about its axle 216, cables222 are further wound around cylindrical axle 216, which results incables 222 pulling laterally inwardly on pivot pins 68′. The pivot pins68′ are then retracted from mounting holes 40 a and 62 a, as rotationalmovement of handle 200 and the corresponding movement of cables 222overcome the force provided by compression springs 232 so as to allowinward movement of pivot pins 68′. A cross pin 68′b preferably extendsoutwardly from either side of ends 68′a of each pivot pin 68′, in orderto prevent over insertion of pivot pins 68′ through the openings inguide bushings 72 by compression springs 232, and to provide bearingpoints for springs 232.

As shown in FIG. 20, lift arm assembly 16′ further includes a supportstand assembly or kickstand 238 which provides support of lift armassembly 16′ and draw latch assembly 18 when they are not connected topush beam assembly 14 on vehicle 12. Support stand 238 includes avertical support leg 238 a and a support foot 238 b and is pivotableabout a bracket 242 that is welded or otherwise secured to one of a pairof side hydraulic cylinders 244. Side hydraulic cylinder 244 extendsoutwardly on either side of lift arm assembly 16′ from cylinder bracket70 to the plow blade assembly 24 and provides for turning plow blade 24to one side or another. Support stand 238 may be positioned in a loweredor support position, as shown in FIG. 20, or may be pivoted to a raisedposition, as shown in FIG. 21 when the hitch assembly is attached tovehicle 12. Although shown as being pivotably secured to a hydrauliccylinder, clearly support stand 238 may be positioned elsewhere on liftarm assembly 16′ without affecting the scope of the present invention.

When handle 202 is pivoted to its upward position, cables 222 arewrapped further around cylindrical axle 216, which results in pivot pins68′ being held in a retracted position from mounting holes 40 a and 62a. In this upward position of handle 202, spring pin 212 of middlelateral member 210 is positioned forwardly of an upwardly extendingflange 214 c on L-shaped bracket 214 (FIG. 20). Spring pin 212 is biasedto be in a lowered position such that a side of pin 212 engages aforward edge of flange 214 c, thereby substantially locking handle 202in its upright position and preventing accidental rearward or downwardrotational movement of handle 202 relative to lift arm assembly 16′.Furthermore, when handle 202 is in its raised position, cylindrical axle216 is in its lowered position as it rotates eccentrically aboutcircular disks 218. This results in connecting members 220 also beinglowered such that lift stop links 204 are correspondingly lowered totheir lowered position within channels 82 a in order to engage and limitrearward movement of slide pin 104 c of draw latch assembly 18 alongchannels 82 a, as discussed above with respect lift stop links 80 oflift arm assembly 16. This allows hydraulic cylinder 28 to operate drawlatch assembly 18, but not raise lift arm assembly 16 as mentionedabove.

After vehicle 12 has been positioned in proper alignment with lift armassembly 16′ and draw latch assembly 18, draw latch assembly 18 isoperable as described above to pull the plow and hitch assembly intoproper alignment with the mounting brackets of push beam assembly 14 onvehicle 12. Once the mounting holes 40 a and 62 a of mounting brackets40 and 62, respectively, have been properly aligned, handle 202 may berotated downwardly to allow engagement of pivot pins 68′ with mountingholes 40 a and 62 a (FIGS. 21 and 22). This is accomplished by firstpulling upward on spring pin 212 such that a lower end 212 a of springpin 212 clears flange 214 c on L-shaped bracket 214 to allow forwardrotation of handle 202. As handle 202 is then pivoted downward, cables222 are unwound from cylindrical axle 216, which allows compressionsprings 232 to push pivot pins 68′ through the corresponding mountingholes on the mounting brackets of lift arm assembly 16′ and push beamassembly 14. Furthermore, as handle 202 is pivoted downward, cylindricalaxle 216 is rotated upwardly due to eccentric positioning with respectto circular disks 218. This results in an upward movement of connectingmembers 220 and a corresponding upward movement of lift stop links 204.As discussed above with respect to lift stop links 80, an upwardmovement of lift stop links 204 removes lift stop links 204 from thepath of slide pin 104 c along channel 82 a, such that slide pin 104 cmay continue travelling rearwardly along channel 82 a. This again allowsfor relative rotation between draw latch assembly 18 and lift armassembly 16′, such that actuation and extension of cylinder 28 resultsin a raising or lowering of a forward end of lift arm assembly 16′ andplow blade 24. As shown in FIG. 21, support stand assembly 238 may bepivoted upward to a raised position when lift arm assembly 16′ has beensecured to push beam assembly 14 on vehicle 12.

Second Alternate Embodiment

In another alternate embodiment of the present invention, a hitchassembly 300 (FIGS. 23 and 24) includes push beam assembly 14 and lighttower assembly 20 of hitch assembly 10 and the lift arm assembly 16′discussed above with respect to hitch assembly 200, and a draw latchassembly 18′. Draw latch assembly 18′ is substantially similar to and isoperable in substantially the same way as draw latch assembly 18.However, each draw link 102′ of draw latch assembly 18′ includes adownward depending support section 302. Support sections 302 function tosupport the lift arm assembly 16′ and draw latch assembly 18′ when theyare not connected to push beam assembly 14 on vehicle 12. Supportsections 302 are preferably integrally formed with the curved hooksections of draw links 102′ and are connected at a lower edge by alaterally extending foot portion 304. Foot portion 304 provides asubstantially flat lower surface 304 a, which rests upon the ground inorder to provide stable support of the assembly when it is not connectedto a vehicle.

Because support sections 302 are integrally formed with draw links 102′,support sections 302 pivot with respect to lift arm assembly 16′ aseither draw links 102′ are pivoted about mounting links 100 or mountinglinks 100 are pivoted about pivot axis 130 a. Because support sections302 determine the height at which the assembly is supported, thisresults in a raising or lowering of draw latch assembly 18′ and lift armassembly 16′ as hydraulic cylinder 28 is either extended or retracted.By providing vertical adjustment of plow and hitch assembly 300 prior tovehicle 12 being driven into position substantially above the mountinglinks 100 and draw links 102′, hitch assembly 300 may be easily set toan appropriate height at which vehicle 12 may be driven forward intoposition. Once vehicle 12 is in its proper position above mounting links100 and draw links 102′, draw latch assembly 18′ and lift arm assembly16′ function to draw or pull the assemblies into position relative topush beam assembly 14 and further to pivotably secure the lift armassembly 16′ to push beam assembly 14, as discussed in detail above withrespect to plow assemblies 10 and 200. Because support sections 302 areincluded on draw latch assembly 18′, a support stand assembly is nolonger necessary on lift arm assembly 16′. Although shown and describedwith draw latch assembly 18′ being implemented with lift arm assembly16′, clearly the present invention provides for implementing draw latchassembly 18′ with lift arm assembly 16. Support stand assembly 88 maythen be eliminated from lift arm assembly 16, provided that a lever orother alternative means for raising and lowering lift stop link 80 isthen provided on lift arm assembly 16.

Referring now to FIG. 25, a schematic is shown of the hydrauliccylinders and their interconnection with power source 56 and the snowplow assembly and plow blade 24. Most preferably, the snow plow assemblyof the present invention includes a plow blade assembly 24 which furtherincludes laterally extending wings 310 which may be pivoted forwardlywhen extended, as disclosed in commonly assigned U.S. Pat. No.5,638,618, issued to Niemela et al., and co-pending, commonly assignedU.S. patent application Ser. No. 08/874,008, filed Jun. 12, 1997, thedisclosures of both of which are hereby incorporated herein byreference. In order to provide lateral extension and forward folding ofwings 310, plow blade assembly 24 preferably includes a pair ofoppositely directed hydraulic cylinders 312 a and 312 b which extend andretract the wings laterally and a pair of smaller oppositely directedhydraulic cylinders 314 a and 314 b positioned laterally outwardly fromcylinders 312 a and 312 b, respectively. Hydraulic cylinders 314 a and314 b pivot the wings 310 forwardly about a pivot axis 310 a when thewings are extended and the cylinders 314 a and 314 b are activated bypower source 56. The snow plow and hitch assembly 10 also preferablyincludes a pair of hydraulic cylinders 244 a and 244 b interconnectedbetween brackets 70 of lift arm assembly 16 or 16′ and the plow bladeassembly 24. Hydraulic cylinders 244 a and 244 b may be individuallyextended to provide a left or right angling or turning of the plowassembly 24 relative to the lift arm assembly and vehicle 12. Asdiscussed above, hitch assembly 10, 200 or 300 most preferably furtherincludes hydraulic cylinder 28 which provides lifting and lowering ofsnow plow blade assembly 24 and actuation of draw latch assembly 18 or18′.

In order to activate the various cylinders included in the plow assembly24 of hitch assembly 10, 200 or 300, power source 56 includes ahydraulic pump 316, which draws hydraulic fluid 318 from a reservoir320. An operator of the snow plow may then selectively energize one ormore of a plurality of solenoid valves interconnected with power source56 and pump 316, so as to extend and/or retract one or more of thehydraulic cylinders of hitch assembly 10, 200 or 300 or plow bladeassembly 24. Pump 316 and the associated solenoid valves arerepresentative of such components commonly used in snow plow assembliesand are operated in a conventional manner.

As shown in FIG. 25, each hydraulic cylinder is connected to a pair offluid lines, each of which is connected at an opposite end to at leastone solenoid operated valve. The solenoid operated valves function todirect pressurized hydraulic fluid from the power source 56 into theselected hydraulic cylinder in order to either extend or retract thepiston rods of the cylinder. Pressure release valves may also beincluded within the system in order to prevent over pressurization ofeach of these cylinders upon plow blade assembly 24 encountering anobstacle or any other event which may cause additional pressure to bebuilt up within the fluid lines.

In order to raise or lower plow blade assembly 24 and/or to activatedraw latch assembly 18 or 18′, the appropriate solenoids must beenergized in order to open or close the valves connected with thehydraulic fluid lines connected to either end of hydraulic cylinder 28.More specifically, in order to raise the plow blade assembly 24 or raiseand pivot the lift arm assembly and draw latch assembly, a solenoid S6is energized to pressurize fluid line 324, which is connected to an end28 a of hydraulic cylinder 28, and an electrically operated check valveS7 is opened to allow fluid in a line 326 to flow from a rod end 28 b ofhydraulic cylinder 28 back into reservoir 318, as cylinder 28 isextended. Conversely, in order to lower plow blade assembly 24 ordisengage draw latch assembly 18 or 18′ from push beam assembly 14,pressure is applied at the rod end 28 b by activating a solenoid S8 topressurize fluid line 326 and further opening a second electricallyoperated check valve S5 to allow fluid to return to reservoir 318through fluid line 324. When in a plow or “float” mode, both of thecheck valves S5 and S7 are opened to connect both of the ends 28 a and28 b of the hydraulic cylinder to the reservoir 320 in order to allowthe rod 28 d of hydraulic cylinder 28 to extend or retract in responseto the plow blade contacting an object while plowing.

The other cylinders 244 a, 244 b, 312 a, 312 b, 314 a and 314 b of theplow assembly are operated in a similar manner as discussed above.Briefly, in order to angle plow blade assembly 24 to the right, asolenoid S3 is energized to provide pressure to a left hydrauliccylinder 244 a through a supply line 328. Conversely, in order to angleplow blade assembly 24 to the left, a solenoid S4 is energized toprovide pressurized fluid through supply line to a right hydrauliccylinder 244 b. Furthermore, in order to extend the wings 310 laterallyoutwardly along plow blade 24, a solenoid S2 is energized to extend lefthydraulic cylinder 312 a and/or a solenoid S10 is energized to extendright hydraulic cylinder 312 b. If it is desired that one or both of thewings 310 are to be pivoted forwardly about axis 310 a, solenoids S2 andS10 remain energized until cylinders 312 a and b are fully extended, atwhich point pressure may be supplied to the outer cylinders 314 a and314 b, respectively. This is accomplished by a pair of delay valves orpressure relief valves 332 and 334 which only allow pressurized fluid tobe supplied to hydraulic cylinders 314 a and 314 b after hydrauliccylinders 312 a and 312 b have been fully extended. This is preferred inorder to prevent wings 310 from being pivoted forwardly when plow bladeassembly 24 is not in its fully expanded position. The wings areunfolded and retracted in a similar manner by activating solenoid S1and/or S9, which provide pressure to the opposite end of the cylindersin order to retract the cylinders. Again a pair of hydraulic reliefvalves 336 and 338 are provided in order to delay retraction ofcylinders 312 a and 312 b until outer cylinders 314 a and 314 b havefully retracted, such that wings 310 are in a substantially straightposition before they are laterally retracted by cylinders 312 a and 312b.

Therefore, all of the fluid cylinders can be controlled with theircorresponding solenoid operated fluid valves. These valves mostpreferably have an electronic control panel in the cab of the vehiclefor easy access and operation by the driver. This allows the driver ofthe vehicle to adjust the plow assembly without leaving the vehicle cabwhich further allows the plow assembly to be operated while the vehicleis being driven. By providing remote control of all aspects of the plowblade assembly from within the vehicle, the efficiency of plowing snowor the like is greatly increased, as the operator of the plow does nothave to repeatedly stop the vehicle and get out of the cab in order toadjust the plow blade assembly 24 in response to encountering differentconditions.

Therefore, the present invention provides a plow hitch assembly whichallows for an easy and efficient attachment of a plow blade and lift armassembly to the vehicle. This is accomplished without requiring theoperator of the plow to manually adjust the plow assembly verticallyand/or laterally in order to align the assembly with the vehicle. Thepresent invention further provides for an easy pivotal connection of thelift arm assembly to the push beam assembly without requiring separatemanual insertion of pivot pins through mounting brackets and thenfurther insertion of a lock pin in order to prevent accidental removalof the pivot pins while the plow is in use.

While several forms of the invention have been shown and described,other forms will forms will now be apparent to those skilled in the art.Therefore it will be understood that the embodiments shown in thedrawings and described above are merely for illustrative purposes, andare not intended to limit the scope of the invention which is defined bythe claims which follow as interpreted according to the principals ofpatent law, including the Doctrine of Equivalents.

The embodiments of the invention in which an exclusive property right orprivilege is claimed are defined as follows:
 1. A draw latch assemblyadapted for pulling a plow assembly toward a vehicle and mounting theplow assembly on the vehicle, the vehicle having a plow mountingportion, the plow assembly having a first end and a second end, thefirst end of said plow assembly having a plow blade, the second end ofsaid plow assembly being adapted to removably connect to the plowmounting portion of the vehicle, said draw latch assembly comprising: adraw latch interconnected to the plow assembly, said draw latch beingoperable to move relative to the plow assembly so as to engage themounting portion of the vehicle and pull the plow assembly toward thevehicle for connection thereto.
 2. The draw latch assembly of claim 1,wherein said draw latch is pivotably mounted at the plow assembly and ispivotable to engage the mounting portion of the vehicle and pull theplow assembly toward the vehicle.
 3. The draw latch assembly of claim 2further including an actuator which is operable to pivot said draw latchrelative to the plow assembly.
 4. The draw latch assembly of claim 3,wherein the plow assembly is removably and movably mountable to thevehicle, said actuator being further operable to pivot said draw latchto vertically adjust the plow blade.
 5. The draw latch assembly of claim1, wherein said draw latch is movable to engage the mounting portion ofthe vehicle, said draw latch including a support foot which is operableto support the second end of the plow assembly when the plow assembly isremoved from the vehicle.
 6. The draw latch assembly of claim 5, whereinsaid draw latch and said support foot are movable to adjust a height ofthe second end of the plow assembly when the plow assembly is removedfrom the vehicle.
 7. The draw latch assembly of claim 1, wherein theplow assembly is pivotally mountable to the vehicle, the plow assemblybeing pivotable relative to the vehicle to vertically adjust the plowblade.
 8. The draw latch assembly of claim 7 further including a movablemember which is movably interconnectable with said draw latch, saidmovable member being movable to a first position, where said draw latchis operable to engage the mounting portion of the vehicle and pull theplow assembly toward the vehicle for connection thereto, and to a secondposition, where said draw latch is operable to vertically adjust theplow blade when the plow assembly is connected to the plow mountingportion of the vehicle.
 9. A plow hitch assembly adapted for mounting aplow on a vehicle, the vehicle having a plow mounting portion, said plowhitch assembly comprising: a lift arm assembly having a first end and asecond end, said first end of said lift arm assembly being adapted forconnection with a plow blade, said second end of said lift arm assemblybeing adapted to removably and movably connect to said plow mountingportion of the vehicle; and a draw latch assembly interconnected to saidlift arm assembly, said draw latch assembly including a movable memberwhich is movably interconnected with said draw latch assembly, said drawlatch assembly being selectably operable in a first mode, where saiddraw latch assembly is operable to engage the mounting portion of thevehicle and move said lift arm assembly toward the vehicle forconnection thereto, and a second mode, where said draw latch assembly isoperable to vertically adjust the plow blade at said first end of saidlift arm assembly when said lift arm assembly is connected to the plowmounting portion of the vehicle, in response to movement of said movablemember.
 10. The plow hitch assembly of claim 9, wherein said movablemember comprises a support stand which supports said second end of saidlift arm assembly when said lift arm assembly is removed from thevehicle.
 11. The plow hitch assembly of claim 10, wherein said supportstand is movable between a support position, whereby said draw latchassembly is operable to engage the vehicle and move said lift armassembly toward the vehicle, and a raised position, whereby said drawlatch assembly is operable to vertically adjust the plow blade.
 12. Theplow hitch assembly of claim 9, wherein said movable member isinterconnected with a connector at said lift arm assembly which ismovable between an engaged position, where said connector engages theplow mounting portion of the vehicle to movably connect said lift armassembly to the vehicle, and a disengaged position, where said connectoris moved from said engaged position, in response to movement of saidmovable member, said draw latch assembly being selectably operable toengage the vehicle and move said lift arm assembly when said connectoris in the disengaged position and to vertically adjust the plow bladewhen said connector is in the engaged position in response to movementof said movable member.
 13. The plow hitch assembly of claim 9, whereinsaid draw latch assembly further includes an actuator which is operableto move at least a portion of said draw latch assembly relative to saidlift arm assembly to engage the vehicle, move said lift arm assemblytoward the vehicle and vertically adjust the plow blade relative to thevehicle.
 14. A plow connection assembly adapted for mounting a plow on avehicle, the vehicle having a frame, said plow connection assemblycomprising: a push beam assembly mounted to the frame of the vehicle; alift arm assembly having a first end and a second end, said first end ofsaid lift arm assembly being adapted for connection with a plow blade;first and second mounting portions, one of said first and secondmounting portions being mounted at said push beam assembly and the otherone of said first and second mounting portions being mounted at saidsecond end of said lift arm assembly; said first mounting portionincluding a pair of oppositely flared members which are flared laterallyoutward from one another, and a middle member interconnected to one ofsaid oppositely flared members by a guide member, said middle member andat least one of said oppositely flared members having an aperturetherethrough, said apertures being coaxial with a passageway at leastpartially through said guide member; said second mounting portionincluding a slotted member having an open slot at an end thereof and amounting member having an aperture therethrough, said open slot beingflared vertically outwardly at said end of said slotted member; whensaid lift arm assembly is moved toward said push beam assembly, saidslotted member engages said guide member to vertically adjust saidsecond end of said lift arm assembly while at least one of saidoppositely flared members of said first mounting portion engage at leastone of said members of said second mounting portion to laterally adjustsaid second end of said lift arm assembly, said second end of said liftarm being vertically and laterally adjusted to align said apertures ofsaid first mounting portion with said aperture of said second mountingportion; and at least one pivot member which is insertable through saidapertures in at least one of said oppositely flared members and saidaperture in said mounting member and further insertable at leastpartially through said passageway of said guide member to pivotallyconnect said first mounting portion to said second mounting portion,thereby pivotally connecting said second end of said lift arm assemblyto said push beam assembly.
 15. The plow connection assembly of claim14, wherein said passageway of said guide member extends entirely alongand through said guide member, said pivot member being insertablethrough said apertures in said first and second mounting portions andthrough said passageway in said guide member.
 16. The plow connectionassembly of claim 15, wherein said pivot member includes a biasingmember which is operable to bias said pivot member in an insertedposition, whereby said pivot member extends through said apertures andsaid passageway of said first and second mounting portions.
 17. The plowconnection assembly of claim 15, wherein said pivot member isinterconnected to a lever, whereby said pivot member is movable todisengage from said aperture in said mounting member of said secondmounting portion in response to movement of said lever in a firstdirection.
 18. The plow connection assembly of claim 17, wherein saidpivot member includes a biasing member which biases said pivot membertoward an engaged position, where said pivot member is inserted throughsaid apertures and said passageway of said first and second mountingportions, said biasing member moving said pivot member into the engagedposition in response to movement of said lever in a second direction,said second direction being generally opposite said first direction. 19.The plow connection assembly of claim 17 further including a draw latchassembly movably mounted to said lift arm assembly and operable toengage said push beam assembly and pull said lift arm assembly towardsaid push beam assembly, said first and second mounting portionsvertically and laterally adjusting said second end of said lift armassembly as said draw latch assembly pulls said lift arm assembly towardsaid push beam assembly.
 20. The plow connection assembly of claim 19,wherein said draw latch assembly is further operable to pivot said liftarm assembly about said pivot member to vertically adjust the plow bladerelative to the vehicle.
 21. The plow connection assembly of claim 20,wherein said draw latch assembly is selectably operable to engage saidpush beam assembly and pull said lift arm assembly and to pivot saidlift arm assembly about said pivot member in response to movement ofsaid lever.
 22. The plow connection assembly of claim 14 furtherincluding a draw latch assembly movably mounted to said lift armassembly and operable to engage said push beam assembly and pull saidlift arm assembly toward said push beam assembly, said first and secondmounting portions vertically and laterally adjusting said second end ofsaid lift arm assembly as said draw latch assembly pulls said lift armassembly toward said push beam assembly.
 23. The plow connectionassembly of claim 22, wherein said draw latch assembly is furtheroperable to pivot said lift arm assembly about said pivot member tovertically adjust the plow blade relative to the vehicle.
 24. The plowconnection assembly of claim 14, wherein said first and second mountingportions comprise a pair of first and second mounting portionspositioned toward lateral ends of said second end of said lift armassembly and of said push beam assembly, said apertures of said pair ofsecond mounting portions being coaxially aligned and said apertures andsaid passageway of said pair of first mounting portions being coaxiallyaligned.
 25. A draw latch assembly adapted for moving a plow assemblytoward a vehicle and mounting the plow assembly on the vehicle, thevehicle having a plow mounting portion, the plow assembly having a plowblade and a mounting portion adapted to removably connect to the plowmounting portion of the vehicle, said draw latch assembly comprising: adraw latch movably interconnected to the plow assembly, said draw latchbeing movable relative to the plow assembly so as to engage the plowmounting portion of the vehicle and move the mounting portion of theplow assembly toward the vehicle for connection thereto; and a supportfoot connected to said draw latch, said support foot being operable toat least partially support the plow assembly when the plow assembly isremoved from the vehicle, said support foot being movable with said drawlatch to adjust a height of the mounting portion of the plow assemblywhen the plow assembly is removed from the vehicle.
 26. The draw latchassembly of claim 25, wherein said draw latch and said support foot aremovable relative to the plow assembly to vertically adjust the mountingportion of the plow assembly to generally align the mounting portion ofthe plow assembly with the plow mounting portion of the vehicle.
 27. Thedraw latch assembly of claim 25, wherein said draw latch is pivotallymounted to the plow assembly and is pivotable relative to the plowassembly to pull the plow assembly toward the vehicle.
 28. The drawlatch assembly of claim 27, wherein said draw latch is further pivotableto vertically adjust the plow blade relative to the vehicle.